Hot-air syringe



0. H. AND A. F. PIEPER.

HOT AIR SYRINGE.

APPLICATION FILED AUG. I3. 1917.

1,388,526. Patented Aug. 23, 1921.

' Arme/vers W/ TN E SSE S:

UNITED STATES PATENT OFFICE.

OSCAR H. PIEPEB AND ALPHONSE F. PIEPEB., OF ROCHESTER, NEW YORK.

HOT-AIR SYRINGE.

Specication ot Letters Patent.

4Patented Aug. 23, 1921.

Application led August 13, 1917. Serial No. 185,863.

To all 'whom t may concern Be it known that we, OSCAR H. PIEPER and ALPHONSE F. PTErER, both of Rochester, in the county of Monroe and State of New York, have invented certain new and useful Im rovements in Hot-Air Syringes; and we do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of this specification, and to the reference-numerals marked thereon.

Our present invention relates to hot air syringes such as those employed by dentists for cleaning and drying cavities in teeth, and embodies generally a hand piece connected to a source of compressed air, an electrical heating coil past which the air is conducted and controlling means for the air and heating coil, whereby the iiow of air past the coil takes place simultaneously with the admission of current therethrough. More specifically our invention relates to certain improvements in the arrangement of the parts whereby the heating coll is rendered more effective, and the hand piece constructed so as to enable the various passages to be easily formed and the parts readily assembled, in such a manner as to obtain air tight joints and perfect insulation. To these and other ends the invention consists in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

In the drawings:

Figure 1 is an enlarged longitudinal sectional view of a hot air syringe constructed in accordance with our invention;

Fig. 2 is an elevation looking from the right in Fig. 1, parts of the view being shown in section;

Fig. 3 is a horizontal sectional view on the line 3 3 of Fig. 2;

Fig. 4 is an enlarged view of the heating element removed;

Fig. 5 is a detail view of the sustaining member for attaching one end of the heating coil, and

Fig. 6 is a sectional view on the line 6 6 of Fig. 4.

Similar reference characters throughout the several views indicate similar parts.

A syrlnge constructed in accordance with our inventlon embodies a body portion compr1s1n a head portion 1, on which is fitted a tn bu ar hand grip 2, and having a recess recelvlng the casing 4, containing the heating element 5 and carrying the nozzle 6 at 1ts o uter end, The head 1 has a portion contamlng the a1r passages which is connected to the pipe 7 leading to a source of air under pressure and within the hand grip 2. With- 1n the head is a valve chamber 9 containing a valve head 10, on a stem 11, having a thumb piece 12 on its outer end. The valve head 1s normally held against its seat by a spring 13, resting in a recess in a screw plug 14, removably closing the valve chamber. The heating element 5 is shown in detail 1n Flg. 4 `and consists of an outer tube 15 closed at its inner end 16, and expanded at its outer end, as at 17, to receive a correspondingly expanded end 18 on an inner tube 19 which is spaced from the outer tube to provide an air passage between them. Within the inner tube is located the heating coil C of fine elastic wire, one end of the coil being looped under the head of a screw 20, which passes through insulating washers 21, on each side of the end 16 of the outer tube, and secured by a lockl nut 22. The other end of the heating element, or coil, is engaged by a hook 23 on a transversely extending portion 24 of a ring 25 which is placed within the expanded end 18 of the inner tube and held thereon by a washer 26 over which the end 17 of the outer tube is formed. The heating coil C is supported solely by means of the attaching portions at its opposite ends and in order to prevent any accidental contact of the coil with the tube 19, and consequent short circuiting of part of the coil, we provide an insulating sleeve 19a fitting within said tube and surrounding the coil.

The heating element is located within the casing 4 and is secured therein by means of the screw 20, which cooperates with a securing member in the form of a hollow sleeve 27 permanently fastened by means of a nut 28 to an insulating disk 29 set within the end 3 of the head l. The disk 29 is prevented from removal by engagement therewith, of a flange 30 on a tube, or sleeve, 31 surrounding the heating element and s aced therefrom except at its outer end whlch is engaged by the expanded end 17 of the heating element to make an air tight joint. An'

insulating ring 32 bears on the outside of the flange 30, and is forced aga-instit by a shouldered ring 33, which in turn is engaged by the inner end of the casmg 4, and secured by means of the latter, which is itself threaded into the recess of the head 1. A sleeve 55 of asbestos, or other poor conductor of heat, is inserted between the tube 31 and the outer casing, or sheath, 4 to prevent loss of heat by radiation from the coil C.

Theair is admitted `by the valve 10 from the passage 8 into a passage 34 in and through la central recess 35 and transverse apertures 36 in the sleeve 27. It then passes between the tube 31 and the outer wall 15 of the heating element, until it reaches apertures 37 in the latter, which are adjacent the ex anded end 17. The air then passes inwar ly between the tubes 19 and 15, of the heating element, and around the end of the inner tube, in the opposite direction within the tube 19, past thev heating coil and through the recesses in the ring 25 and the central aperture in the washer 26, escaping through the nozzle 6.

In order to enable the circuit through the coil C to be closed when the air is admitted, we provide a switch arm 38 which is actuated by a. plunger 40 arranged beneath the valve thumb piece 12 and is adapted to engage with an insulated contact plate 41 connected by a wire 42, passing through a channel 42a in the head 1 and through the sleeve 27 to the tube 31. The switch arm 38, which makes electrical contact through the tubes 15 and 19, to one end of the heating coil C, is carried by an air supply pipe attaching sleeve 43, insulated from the head 1, at 55, the sleeve being provided with a central aperture to receive a tubular portion 45 which is insulated therefrom by Washers 46 and secured therein by the nut 47. The portion 45 is provided at its upper end with a lateral opening 48 registering with a similar opening leading into the passage- 8. A suitable insulating washer 49 is inserted between the proximate faces of the members 1 and 45 and an air tight connection obtained by means of the clamping screws 50 (Figs. 2 and 3) passing through ears 5()a on the member 45 and insulated therefrom, as indicated by 5l.

The member 45 is connected by a wire 52 leading through a channel 52'l to the nut 28, the latter makingl electrical connection through the sleeve 27 and screw 2O to the inner end of the heating coil. Electrical connection is preferably made -to an electric circuit by wires A and B which lead within the air pipe 7, and are connected respectively to outer and inner contact sleeves 53 sleeve 43, while the latter makes contact with the tubular member 45 which constitutes the other terminal of the instrument circuit. lVhen the thumb piece 12 of the valve is de ressed, the current passes from conductor X, sleeves 53 and 43, switch arm 38, contact plate 41, wire 42, tube 31, heating element C, screw 20, sleeve 27, nut 28, wire 52, tubular member 45, sleeve 54, conductor B. At the same time air is admitted from the pipe 7 through the central passages in the contact sleeves 53 and 54, through member 45, assage 8, valve chamber 9, and as before escribed past the heatin coil into the nozzle 6.

t will be observed from the foregoing that the air conducting portion carrying the nozzle and the heating element therein are both so arran d that they may be assembled independent y of the head and handle portion of the instrument, and secured to the latter by inserting the end of the tube 4 in the recess of the head 1, and screwing it into position v therein. This act causes the compression of the collar 33 against the washer 32 bearing against the flan ed end 30 of the interior sleeve 31, whic in turn compresses the washer 29 and causes the sleeve mounted thereon to be rigidly held in place. The present construction of the handle portion of the instrument contained within the sheath 2 possesses certain advantages in that We have provided means for adequately insulating the metal parts of the head proper and nozzle portion of the instrument and utilizing only the leading-in portion of the air pipe and handle connection as part of the circuit, as shown in Fig. 2, in contradistinction to those instruments wherein one side of the circuit is composed of the metal portions of the instrument itself. To accomplish this object and facilitate the assembling of the parts in such a Way as to provide for their necessary rigidity and lessen the liability of their becoming loosened in service, especially by the frequent removal and application of the air pipe we make the handle portion as a continuation of the head, formin the Whole out of a single piece of metal w ich is drilled into at one end to provide a recess of lar diameter, as indicated by X, into which air passage part 45 and the attaching sleeve 43 are inserted and secured within the insulating bushin 55. The inner end, or bottom, of the recess is cut into, or exposed by transversely removing the metal stock, thus providing space for the accommodation of the switch spring 38 and,

what is more important, providing accommodation for and access to the screws 50 by,

which latter, it will be observed, is drilled in at the bottom of therecess X near the side of the latter, and the open end plugged at 56. This arrangement of the parts, it will be observed, enables the member 45 to be arranged, centrally within the sleeve 43, whereby a satisfactory union is effected in the joint formed between the outer end of the part 45 and the sleeve 54, as the latter is brought into position by rotating the hose connection 53 on its thread in the end of the sleeve 43.

A feature not previously mentioned of importance in a device of this kind is the construction of the nut, or plug 14, closing the aperture below the air valve 10. The inner end of. this nut is recessed to accommodate the spring 13 and beneath the latter and the shoulder formed at the bottom of the recess is a screen plate 14a overlying the thin layer of cotton 14", these two foraminous coverings acting as a strainer for the air, which arrests particles of dust preventing them from passing through the syringe, or becoming lodged on the valve seat.

We claim as our invention:

1. In an air syringe, the combination with a body having a recessed outer end and a transversely extending seat, of a sleeve located within the recess and having an inner end fitting the seat, a securing device fastening the end of the sleeve on the seat, said body and sleeve being provided with air passages each having laterally communicating portions formed therein at the vpoint of union of the sleeve and seat.

2. In an air syringe, the combination with a body having a portion cut away at one side forming a transverse seat and provided with an air passage leading therefrom, of a sleeve extending in the direction of the bod and having a lateral face fitting the seat and provided with a passage communicating with said air passage, and a fastening device serving to hold the sleeve against theseat and operating in a direction transversely of the sleeve and body.

3. In an air syringe, the combination with a body member substantially 'circular in cross section having a portion cut away at one side to form a transverse seat and provided with an air passage leading therefrom, of a sleeve extending axially of the body having a lateral face fitting against the seat and provided with a passage coperating with that of the body and fastening devices uniting the sleeve to the seat on the body.

4. In an air syringe, the combination with a head having a body portion provided with a hollow outer end and having a longitudinal air passage disposed eccentrica'lly and provided with a laterally extending extremity, of a sleeve within the hollow end of the body havin the inner end of its passage t e opening lateral y and coperatlng with similarly formed end of the air passage, a securing device uniting the end of the sleeve to the body adjacent the point of communication of said passages.

5. In an air syringe, the combination with a substantially cylindical body having a recessed outer end and a cutaway portion forming a transversely extending seat at the inner end of the recess, said body having an air passage terminating at said seat, of a sleeve extending axially of the body within the recess therein havin a face portion iitting against the seat am? also provided with a passage communicating with the air passage of the body, and securing devices fastening the sleeve to the seat.

6, In an air syringe, a body portion formed with a bore adjacent one end thereof and with a laterally disposed seat adjacent the inner end of the bore, a nozzle on the other end of the body portion, a sleeve in said bore with a laterally disposed seat secured to the seat of the body portion, said body portion and sleeve having passages therein communicating with each other through said seats and with said nozzle, and a valve controlling said passages.

7. In an air syringe, a body portion formed with a bore therein adjacent one end and with a laterally disposed seat adjacent the inner end of the bore, a nozzle on the other end of the body portion, a sleeve in said bore with a laterally disposed seat, means for detachably securing the seat of the sleeve to the seat of the body portion, a tubular hand grip detachably secured to the body portion, affording access to said securing means, said body portion and sleeve having passages therein communicating with each other through said seats and with said nozzle, and a valve controlling said passages.

8. In an air syringe, a body portion formed with a bore adjacent one end thereof and with a laterally disposed seat adjacent -the inner end of the bore, a nozzle on the other end of the body portion provided with an electrical heating means, a sleeve in said bore formed in two insulated sections one of which has a laterally disposed seat cooperating with the seat of the body portion, said body portion and sleeve having air passages communicating with each other through said seats and with said nozzle, an air and electrical supply conduit having two insulated sections each contacting with one of the sections of said sleeve, respectively, and electrical connections between the sections of said sleeve and said heating means in the nozzle.

9. In an air syringe, a body portion formed with a bore adjacent one end thereof and with a laterally disposed seat adjacent the inner end. of the bore, a nozzle on the other end of the body portion provided with an electrical heating means, a sleeve in said bore formed in two insulated sections one of which has a laterall disposed seat coperating with the seat o the body portion, said body/portion and sleeve having air passages communicatin with each other through said seats and wi said nozzle, an air and electrical supply conduit having two insulatedsections each contacting with one of the sections of said sleeve, respectively, electrical connections between the sections of said sleeve and said heatin means and a cornbined air valve and switch controlling sald passages and electrical connections, re-

spectlvely.

- OSCAR H. PIEPER.

ALPHONSE F. PIEPER..` 

